BQ25570 - minimum operation current

Hirotaka Matsumoto

Other Parts Discussed in Thread: BQ25570

Hi all,

Would you mind if we ask BQ25570?

Our customer uses the BQ25570 as following condition;

<Our customer's condition>
Vin : 2.7V, 2.3mA over
Vout : 3.3V or 3.6V

We have one question about minimum operation current of BQ25570.

When Vin current is less than 2.3mA, Vout belows to 2.0V(@2.7mA).

So, how much is minimum operation current in case of Vin=2.7V? 488nA?

Kind regards,

Hirotaka Matsumoto

over 9 years ago

0 Jing Zou over 9 years ago

TI__Mastermind 20570 points

What is the voltage on VSTOR? once the part is out of cold start, the IC should work as far as the input voltage is 100 mV and higher.

If the voltage on VSTOR is less than 1.8V, then the input will be clamped to ~330mV (even though you have a 2.7V input voltage, the internal circuitry will clamp VIN_DC to 330mV). The minimum power for the IC to start up is 15 uW typical.

0 Hirotaka Matsumoto over 9 years ago in reply to Jing Zou

Guru 27585 points

Jing san,

Thank you for your reply!

Kind regards,

Hirotaka Matsumoto

0 Michael Liesenberg85 over 9 years ago in reply to Hirotaka Matsumoto

Mastermind 7560 points

Hi Jing,

i have a 2V Solar Pannel giving a maximum of 44mA current to the BQ25570. The VSTOR is below 1.8V and the VSTOR is clamped to 330mV.
If you say the minimum power would be 15uW to start up, than why in my case does it get clamped around 330mV?
I also attached 2x Solarpannel in series and 2 of the same in parallel. So i have now 4V and 88mA but it stills stays at 330mV the hole time.
Here is my solar pannel ixapps.ixys.com/.../SLMD121H04L_2016_06_22.pdf

Does the size of the battery also matters? I am using a LiOn battery with 3.7V and 2200mAh. Is this too big?

Thanks,

Michael

0 Gautham over 9 years ago in reply to Michael Liesenberg85

TI__Genius 12485 points

Michael,

When it is at 330mV, it is on cold start operation. Since the battery is too big, try disconnecting it to check that VSTOR will rise to >1.6V and to VBAT_OV setting.

Then on connecting the battery, you will notice the change. (Also why is the battery at <330mV? is it completely discharged?)

regards,
Gautham

0 Michael Liesenberg85 over 9 years ago in reply to Gautham

Mastermind 7560 points

Hi Gautham,

i disconnected my MCU from LOAD and connected on the Batt Pin and the BQ25570 got out of the coldstart.
So i think i had too much load on VSTOR at beginning. I can Shutdown the MCU with VBAT_OK siganl so it doenst overdischarged the battery.

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BQ25570 - minimum operation current